1. Field of the Invention
The invention relates to an internal combustion engine.
2. Description of Related Art
In an internal combustion engine, a wall that defines an exhaust passage is exposed to high-temperature exhaust gas. As the temperature of the wall increases due to exposure of the wall to high-temperature exhaust gas, the strength of the wall decreases. In order to reduce generation of, for example, cracks due to a decrease in the strength of the wall, configurations for reinforcing the wall that defines the exhaust passage have been proposed.
For example, Japanese Patent Application Publication No. 2013-189921 (JP 2013-189921 A) describes a turbocharger including a turbine housing formed integrally with an exhaust manifold. In such a turbocharger, the temperature of a continuous portion extending from a collector of the exhaust manifold to a portion that defines a turbine scroll passage, that is, an inlet port of the turbocharger, is likely to become particularly high. Thus, in the turbocharger according to JP 2013-189921 A, in order to reduce strain due to the thermal expansion of the inlet port which is likely to be heated to a high temperature, the rigidity of the inlet port is increased by providing an outer wall of the inlet port with a reinforcing portion that extends continuously from the turbine housing to the exhaust manifold.
The reinforcing portion described in JP 2013-189921 A is provided on the outer wall so as to extend continuously from the turbine housing to the exhaust manifold. As a result, in the turbocharger according to JP 2013-189921 A, the rigidity of the inlet port is uniformly increased.